In your humble correspondent's opinion, one of the major factors governing the usefulness of portable tools in adding value to a road warrior's toolkit and a company's bottom line is battery life. So long as heading out on a sales trip means packing extra batteries in a variety of shapes and sizes, few of them particularly
light or compact, plus a brick-like charger for the laptop and another for the phone and perhaps another for a handheld, the toolkit will get in the way of the work.

We are making progress on the power front, thanks to the combined efforts of device vendors, component manufacturers, and even some transport carriers. As the result of updated BIOS and operating system designs, as well as more powerful batteries with capacities that are inching up toward 5,000 mAh capacity, laptops can now come close to making it across the United states--on a non-stop flight, that is. And some business class seats even have sprouted laptop power ports.

But "making progress" doesn't mean "no longer a problem," unfortunately. Manufacturers of handhelds such as the svelte Palm V and the metal-clad HP Jornada 545 chose form over function and built into the units rechargeable batteries, which means if you're on the road for very long, you'll need to carry the device's charger cradle, as well. (Contrast that with the Palm III or the Handspring Visor, either of which can be rejuvenated with a pair of AAA batteries from any convenience store.)

Phones are both better and worse: Their batteries are removable, so you can carry spares, but the batteries exhaust more quickly, so you must buy and carry more of them. Or recharge them, in which case you're carrying both spare batteries and a brick-like charger.
Since the silicon chips that drive these devices are the power-consumption culprits, chip vendors are racing to lower the power consumption of their chips. In June, for example, Intel introduced for mobile use five fast new processor chips that draw power at the diminutive rate of 1 to 3 watts.

The low-power chip market today is being driven by a much-awaited new company named Transmeta. Founded in 1995 and based in Santa Clara, Calif., the Paul Allen-backed company was one of the best-kept secrets of Silicon Valley until it unveiled in January its Crusoe chip, a small, simple, low-power chip designed explicitly for portable devices. Manufacturers are moving to design the chip into their devices. As they do, Crusoe will pose some tough competition for Intel, given its low cost and the fact that it was designed explicitly to improve the battery performance of small computing devices.

Meanwhile, batteries themselves are changing. Most manufacturers of business tools have by now adopted the lithium-ion battery, which is pricier than the old nickel-cadmium (NiCd) batteries and the newer nickel metal hydride (NiMH) cells, but is lighter in weight and puts out more power. It also is completely free of the "memory effect," which over time diminished the capacity of a battery.

Now heading for the market are two new approaches to batteries. One, the lithium-ion polymer battery, is an advance on today's lithium-ion batteries in that it uses a solid plastic electrolyte rather than a liquid electrolyte solution. As a result, a lithium polymer battery can be very thin and light, and can be shaped or molded to fit an odd-shaped space; in fact, it can be molded so that the case for a device actually is the battery, as well.

However fancy the shape of the Li-poly battery, though, it will still need to be recharged. Hence the interest in the Zinc-air battery, a design that uses
oxygen in the air to oxidize zinc to
generate electricity. This technology produces a strong, steady electric current flow relative to its size, and so has garnered attention for use in miniaturized situations such as hearing aids and pagers. But now an Israeli company, Electric Fuel (www.electric-fuel.com) is offering disposable Zinc-air batteries to fit some Ericsson, Motorola starTAC and Nokia portable phones.

These batteries offer two notable advantages. They're fully charged one-time-use batteries, so no charger is required. At a rating of 3,300 mAh, they supply considerably higher capacity than the 700-900 mAh OEM batteries they replace. That difference can translate into a useful battery life three to five times as long.

We're early in the adoption cycle for Zinc-air batteries, so they're still far too expensive for regular use. But they will come, as will other advances.
For now, though, power, like connectivity and ease of user interaction, remains an issue. Any wireless or mobile deployment project you're considering that doesn't address these factors and how they could get in the way of productivity could itself quickly run out of juice.